Gutenberg: [Navigation Block] Add introductory text to adding a new menu item

[annezazu]

Describe the bug

Currently, when adding a new item to the menu, there's no prompt or introductory text to help nudge the user along. With work being done to expand the number of types of blocks that can be added to the Navigation Block, there should likely be some sort of explanation. Otherwise, it feels a bit like something is broken.

To reproduce
Steps to reproduce the behavior:

1. Open the editor
2. Add the navigation block
3. Select the + to add a new item.

Screenshots

Here's a video of me talking through this issue (and others): https://cloudup.com/c1ChZfDf5ut

Navigation:

General block:

Editor version (please complete the following information):

• WordPress version: 5.4.2
• Does the website has Gutenberg plugin installed, or is it using the block editor that comes by default? Gutenberg plugin
• If the Gutenberg plugin is installed, which version is it? 8.5.1

Desktop (please complete the following information):

• OS: iOS
• Browser: Chrome
• Version: 83.0.4103.116

[noahshrader]

Good catch!

1. I think your suggestion with adding a title to this makes sense to give context to the choices.
2. We should remove the "Browse All" button as there are only two options and opening the left sidebar is unnecessary as all options are shown in the quick library.
3. From a dev standpoint, we should take another look at how we're styling elements within the library containers so that it degrades well (the removal of the search box completely collapses the top padding, as shown in your screenshots)

Attached is a super quick example of the added section heading:

[MichaelArestad]

Currently, when adding a new item to the menu, there's no prompt or introductory text to help nudge the user along. With work being done to expand the number of types of blocks that can be added to the Navigation Block, there should likely be some sort of explanation. Otherwise, it feels a bit like something is broken.

@annezazu is what Noah proposed what you are expecting or were you proposing something more like a walkthrough or popover with more information?

[annezazu]

Ah apologies. I reacted with a heart but should have used my words ;) I dig what Noah proposed as a minimalist way to lightly introduce this interaction. I wonder if even just saying "Options" is enough in case this kind of situation happens again where a limited set of blocks can be used in the interface. It could help create some nice consistency rather than having unique headers.

Minor note: I definitely think Link should be listed before Search as adding repeated links seems far more likely than a bunch of search boxes.

[MichaelArestad]

In that case. I think Noah's mock works. Let's run with that.

[annezazu]

Sounds good to me!

[mtias]

It feels like the text could even expand a bit more instead of just being a heading. In any case, this seems like a good thing to support in the inserter API (a description? a tip? a heading?) that can be optionally added when blocks are restricted (i.e. when allowedBlocks is present). cc @youknowriad @pablohoneyhoney